Waving to the cheering crowd at the St. Patrick’s Day parade with a giddy Congressman by his side, Irish Republican Army political leader Gerry Adams visited the United States thanks to a special provision put into the law for him more than a decade ago by Sen. Ted Kennedy (D-MA).

And in that time, many other staunch advocates of terrorism have utilized that very same provision in order to come to the United States—including several affiliated with the Taliban.

Simply put, the language Sen. Kennedy inserted into the Immigration and Nationality Act in 1990 states that consular officers cannot refuse a visa to someone on the grounds of advocacy of terrorism. He did this because his pal, Gerry Adams, had been denied a visa because of his role as an advocate for Irish Republican Army terrorism in Northern Ireland.

But while the law has been effective in keeping the door open for Adams—allowing him to march in a St. Patrick’s Day parade yet again this month in Holyoke, Massachusetts—it has also proved a bonanza for people such as the former spokesman for the Taliban and an imam who helped run an Islamic school that is closely tied to the Taliban.

Though Sen. Kennedy has steadfastly refused to close the Gerry Adams loophole (including shortly after 9/11), the State Department has the authority under the law to do so. Yet State has only tweaked it, but has otherwise refused.

(While the Patriot Act grants the Department of Homeland Security the authority to deny visas to those who use a “position of prominence within any country to endorse or espouse terrorist activity,” DHS seems to do so only sporadically.)

So who has gotten in thanks to Sen. Kennedy? For starters, the Gerry Adams provision is almost certainly the reason former Taliban spokesman Rahmatullah Hashemi was able to attain a student visa to attend Yale University. The lengthy New York Times Magazine profile of him that caused quite a stir last month indicated that he was open about his Taliban past, yet he received his visa with ease.

Whichever consular officer granted Rahmatullah’s visa, though, was just following orders. Under the subheading, “Advocacy of Terrorism Not Always Exclusionary,” a high threshold is set, whereby inciting people to commit terrorist acts is not enough cause to deny someone a visa. The visa applicant’s “speech must not only have induced others to undertake terrorist activity, but it must also have been made with the specific intent that such activity would result in death or serious bodily injury.”

That’s not in the law written by Congress, but in the regulations as written by State. And it appears visa applicants are given quite a bit of leeway on that two-part test.

In October 2001, Imam Shabbir Ahmed took to the podium, speaking to an angry mob that was gleefully burning American flags and effigies of President Bush. The slight, bearded man of the cloth exhorted the crowd to wage jihad against the United States. He did this in Islamabad, Pakistan’s capital—at a market that was a stone’s throw from the U.S. Embassy.

Less than three months later, Ahmed was issued a visa and traveled to the United States.

Once he arrived in Northern California in January 2002, the imam worked with his mentor to establish an Islamic school modeled on one the pair had run back in Pakistan. Karachi-based Jamia Farooqia counts many high-ranking members of the Taliban among its graduates and teachers.

Ahmed was deported before he and his mentor could open a U.S. version of Jamia Farooqia, but not until after at least one of his followers allegedly traveled to Pakistan for terrorist training. One member of his flock, U.S.-born Hamid Hayat, 23, is currently standing trial for material support for terrorism for allegedly undergoing terrorism training. Authorities reportedly believe, however, that up to six other young men from Ahmed’s former mosque in Lodi, California also attended terrorism training in Pakistan.

And those are just some of the cases in which the Gerry Adams loophole has benefited cheerleaders for Islamic terrorism.

Those holding out hope that the State Department might use the authority granted it under the law to simply scrap the provision are likely to be sorely disappointed. Consular Affairs currently is run by Maura Harty, the protégé and clone of the founder of the courtesy culture, Mary Ryan. Ms. Harty has largely continued the open door policies of her mentor, particularly in Saudi Arabia, which sent us 15 of the 19 9/11 terrorists.

Which brings us back to Congress. Repealing Kennedy’s handiwork, though, is no small task. Not only would he present quite the roadblock in the Senate, but many members of the House probably would as well. Chief among them would be Rep. Richard Neal (D-MA), who was practically glowing as he marched alongside Adams in the St. Patrick’s Day parade.

One would hope, though, that if Rep. Neal knew that the price of having Adams as his guest was the entry of supporters of Islamic terrorism, that the smile would be wiped off his face. But even if that happened, would it be enough to spur him and Sen. Kennedy into action to close the loophole?